Study of return rate and return time of undeliverable postal letters

Postal questionnaires are widely used to collect data in health research and epidemiologic studies. One problem related to mail surveys is the availability of an up-to-date and accurate list of people in the population from which to draw the sample for the survey. For the identification of incorrect postal addresses it is important that all incorrectly addressed mails are returned as undeliverable. This study examines the proportion of unreturned postal letters that were sent to incorrect addresses. We sent 339 letters to existing addresses throughout Germany, but used fictional names name of persons. Three hundred and three letters (98.2%) were returned as undeliverable. The return rates only slightly differed by layout of the envelopes, region and deliverer.     

Die Aufklärungspflicht bei endoskopischen Operationen

Ohne Zusammenfassung     

Block copolymers with bipyridine containing segments: Synthesis and self-organization by Cu(I) complexation

The synthesis and properties of segmented ABA triblock and (AB)_n multiblock copolymer systems with 6,6′-disubstituted 2,2′-bipyridine (bpy) building blocks B and poly(oxytetramethylene) soft segments A are described. The access to the disubstituted bipyridines in large scale quantities was achieved by modification of conventional synthetic routes. In the presence of copper(I) ions these polymers formed mononuclear [Cu(I)(bpy)₂] complexes in solution through self-assembly. The complexed copolymers were microphase separated systems in bulk with nano to mesoscopic superstructures consisting of copper-bpy complex aggregates in a polyether matrix. The thermal, mechanical and elastomer properties of the block copolymers varied with composition.     

Effects of enteral feedback inhibition on motility,luminal flow,and absorption of nutrients in proximal gut of minipigs

We wanted to clarify whether the postprandial intestinal feedback control activated by nutrients in the distal gut exerts different effects on motility, transit of digesta, and absorption of nutrients in the proximal gut. Additionally, interrelationships among motility, transit, and absorption were to be elucidated because these relationships have only been investigated in the fasted state. In five minipigs, a 150-cm segment of the proximal jejunum was isolated by two cannulas. Motility of the jejunal segment was recorded by multiple strain gauges and analyzed by computerized methods. Markers (Cr- and Cu-EDTA) were used for the measurement of the flow rate, transit time, and absorption of nutrients. After a meal, the test segment was perfused with 2 kcal/min of an elemental diet over a period of 90 min. A feedback inhibition was activated by infusion of nutrients into the midgut at rates of 1–4 kcal/min. Saline was infused as control. With increasing energy loads infused into the midgut, the motility index and the length of contraction waves decreased, whereas the incidence of stationary contractions increased, ie, the motility changed from a propulsive to a segmenting pattern. These modulations of motility were associated with a linear decrease in the flow rate and a linear increase in transit time. Flow and transit were linearly correlated with each other. Additionally, the reduction in flow rate and the delay in luminal transit were associated with a linear increase in the absorption of nutrients. However, the increase in absorption induced by the feedback mechanism was small (7.3–13.4%) compared to the marked inhibition of the motility parameters (54–64%), the flow rate (59%), and the delay of transit (5.8-fold). Feedback control primarily modulated motor patterns and luminal flow, whereas the small increase in absorption was only a side effect due to the longer contact time of the nutrients with the mucosa.The study was supported by the Deutsche Forschungsgemeinschaft, grant Eh 64/6-3.     

Metabolism of aniline and 3-chloroaniline in Pseudomonas acidovorans CA28: Evidence of isofunctional muconate cycloisomerases

Two distinct muconate cycloisomerases are involved in the degradation of aniline and 3-chloroaniline (3-CA) proceeding via the ortho-cleavage pathways in Pseudomonas acidovorans CA28. After partial purification of these two enzymes kinetic investigations resulted in a clear differentiation of aniline-derived muconate cycloisomerase (MC) and 3-CA-derived chloromuconate cycloisomerase (CMC). A further result of this study revealed the simultaneous coexistence of MC and CMC in strain CA28 when grown on a mixture of aniline and 3-CA.     

Urinary oxalate and glycolate excretion in healthy infants and children

The molar ratios of oxalate and glycolate over creatinine were determined in single urine samples of 26 infants and 27 children aged 1–5 years. In 135 children aged 5–16 years, two urine specimens were collected, one before breakfast and one at noon. Oxalate was determined by oxalate oxidase, and glycolate was measured by a colorimetric method (improved chromatotropic acid-sulphuric acid assay after prior purification by cation and anion exchanger). Both ratios (expressed in mmol/mol creatinine and analysed on a log-normal basis) were highest in infants 0–6 months old [mean oxalate 147 (95% confidence interval: 60–360), mean glycolate 175 (72–425)]. The mean oxalate ratio was 72 mmol/mol (29–174) at the age of 7–24 months, 44 (19–101) at the age of 2–5 years and 22 (12–40) in adolescents aged 16 years. Molar glycolate ratios were higher, but disclosed the same pattern. Oxalate and glycolate ratios in fasting urines did not differ significantly from those in noon samples (except glycolate in the oldest age group). Oxalate ratios correlated well with glycolate ratios in children up to 5 years of age only. Random urine samples are thus suitable for screening. However, interpretation of data requires use of age-specific reference values that are based on comparable methods.     

Klinische Wertigkeit einer dermatoskopischen Klassifikation von Clark‐Nävi

Background and objectives: The aim of this study was to evaluate the practical value of the dermatoscopic classification of Clark nevi Patients and methods: Dermatoscopic images of 268 lesions clinically and dermatoscopically diagnosed as Clark nevi were presented to 2 dermatologists without knowledge of the histological diagnosis. The dermatologists evaluated the lesions according to a simplified version of the classification scheme for Clark nevi proposed by Hofmann‐Wellenhof and differentiated between 12 different types of Clark nevi. Results: The most common type of Clark nevus was the reticular‐homogenous type (n = 64, 23,9 %), followed by the globular‐homogeneous type (n = 32, 12 %) and by the homogenous type (n = 30, 11,2 %). The overall inter‐rater agreement between the examiners was moderate to good (kappa = 0,58). The highest level of agreement was found for the peripheral hyperpigmented type (kappa = 0,83). Histologically, 17 lesions (6,3 %) were diagnosed as melanomas. The frequency of melanoma was highest among the peripheral‐hyperpigmented type for one observer and among the homogenous type for the other observer. No melanoma was found among the globular, reticular‐globular, and the central‐hyperpigmented types. Conclusions: A dermatoscopic classification of Clark nevi is practically feasible and allows – to some extent – a risk stratification of Clark nevi, which could be useful for clinical management.